1. Field of the Invention
The invention relates to the production of gases from biomass and solar energy.
2. Background and Related Art
Implementation of the invention relates to altering the electrical properties of fluids while in a transition phase flowing through a specifically designed tube and capturing and storing electrolytic generated energy. This current is drawn and utilized to power a modified photonic galvanic cell during nighttime and clouded days, thereby increasing the production of electrolytic generated elemental hydrogen and oxygen which can be used in a fuel cell.
A photosynthetic dependant living organism biomass suspended in a life supporting liquid environment depends upon an internal electrical charge as part of the photosynthetic process to support growth and reproduction. These microorganisms consume nutrients consisting of a variety of organic minerals found within their liquid environment. These consumed minerals allow the individual microorganism cells to be electrically responsive. The microorganism cells therefore are conductive and as such possess positive and negative polarities. Furthermore the microorganisms' liquid environment itself is electrically conductive and is considered an electrolyte solution due to the mineral and chemical content in solution; its polarity fluctuates in nature in response to environmental changes or can be altered when artificially created.
Some types of photosynthetic microorganisms are capable of absorbing and retaining electrical voltage similar to a voltage capacitor which stores and discharges voltage once a full capacity has been reached. In the case of microorganisms suspended within a conductive liquid medium, once the limit of stored voltage has been achieved, individual cells release their excess voltage into the liquid environment. This charge and discharge activity can be measured with oxygen reduction potential, pH and conductivity meters and reflects the overall electrical state of the growth medium as the photosynthetic organisms uptake minerals, fix these minerals, and discharge gases as part of the photosynthetic and respiration processes.
The Calvin cycle represented in the overall formula: 3 CO2+9 ATP+6 NADPH+6 H+→C3H6O3-phosphate+9 ADP+8 Pi+6 NADP++3H2O, demonstrates the fixing of Hydrogen protons (H+) to create carbohydrate. There has been a lot of attention paid to cellular hydrogen extraction as a potential for fuels and fuel cells.
Extraction of hydrogen from algae has focused principally on alteration of the chemical properties of algae in order to extract fixed hydrogen from the cell. One process requires genetic modification to overcome the perceived problems of oxygen hindering the production of hydrogen. The enzyme that actually releases the hydrogen, a reversible hydrogenase, is sensitive to oxygen. The process of photosynthesis produces oxygen, therefore normally stopping hydrogen production very quickly in green algae. Various genetic approaches attempt to create O2-tolerant mutant versions to result in a commercial H2-producing system that is cost effective, scalable to large production, non-polluting, and self-sustaining. Other methods, such as sulfur deprivation, do release hydrogen, but have not proven to be viable as one has to then recombine sulfur to ensure sustained growth.
Other processes utilize acids and heat to extract hydrogen from biomass. Still other methods using bases as reactants for the production of hydrogen. These methods involves the use of redox chemistry to create hydrogen. While chemical modification can result in the creation of hydrogen, such processes are constrained as large-scale production methods due to difficulties in removing the chemicals as part of an integrated production system. The bases and acids flocculate the biomass rendering it useless for further growth and contaminate the growth medium for reuse. Photosynthetic species, such as algae, can store a large amount of pure hydrogen; however, the method of extraction of elemental hydrogen is dependent on a pyrolysis method for the use of this gas which is not extracted from the biomass prior to use. Thus, there are significant ongoing difficulties in obtaining hydrogen from biomass.
Generating a current within a photonic galvanic cell splits water into its constituent parts. Sun-powered photosynthetically driven biological fuel cells have been utilized for some time. In one device, an electrical fuel cell is formed using two chambers, one placed in sunlight and supplied with nutrients and microorganisms which transfer light energy or photons into chemical energy in the form of algae or carbohydrate, and the other placed in the dark where the chemical energy is released by reducing bacteria that produce compounds that release electrons. A bridge is included in the device to provide a pathway for cations and anions without a transfer of material between chambers. Electrons are released to an anode of the device by sulfites generated from sulfates by bacterial action. The energy of this action is derived from the sun and is stored as bacterial metabolites, these being fed to the bacteria to drive the reduction reaction's generating compounds that, in turn, give up electrons to an electrode element.
In photosynthesis, four photons captured by a chlorophyll pigment system with an average energy of approximately 50 Kcals per einstein (the einstein is used in studies of photosynthesis) are needed to reduce one molecule of nicotinamide adenine dinucleotide phosphate (NADPH) at approximately 53 Kcals per mole. All chlorophyll in oxygenic organisms is located in thylakoids, and is associated with PS II, PS I, or with antenna proteins feeding energy into these photosystems. PS II is the complex where water splitting and oxygen evolution occurs. Upon oxidation of the reaction center chlorophyll in PS II, an electron is pulled from a nearby amino acid (tyrosine) which is part of the surrounding protein, which in turn gets an electron from the water-splitting complex. From the PS II reaction center, electrons flow to free electron carrying molecules (plastoquinone) in the thylakoid membrane, and from there to another membrane-protein complex, the cytochrome b6f complex.
The other photosystem, PS I, also catalyzes light-induced charge separation in a fashion basically similar to PS II: light is harvested by an antenna, and light energy is transferred to a reaction center chlorophyll, where light-induced charge separation is initiated. However, in PS I electrons are transferred eventually to NADP (nicotinamid adenosine dinucleotide phosphate), the reduced form of which can be used for carbon fixation. The oxidized reaction center chlorophyll eventually receives another electron from the cytochrome b6f complex. Therefore, electron transfer through PS II and PS I results in water oxidation (producing oxygen) and NADP reduction, with the energy for this process provided by light (2 quanta for each electron transported through the whole chain). A schematic overview of these processes is provided in FIG. 7. Therefore, the theoretical maximum conversion of photonic energy to reducing potential is approximately 25%. Tapping the energy as formed into carbohydrate leads to another reduction in the theoretical efficiency.
Although, in principle, the nature of the reactants is not limited, the fuel-cell reaction usually involves the combination of hydrogen with oxygen, as shown by Equation (1). At 25° C. and 1 atmosphere pressure, that is, standard temperature and pressure (STP), the reaction takes place with a free energy change (AG) of AG=056.69 kcal/mole, that is, 237,000 joules/mole water.H2(g)+½O2(g)→H2O(l)  (1)
If the reaction is harnessed in a galvanic cell working at 100% efficiency, a cell voltage of 1.23 volts˜ results. In actual service such cells have shown steady-state potentials in the range 0.9-1.1 volts, with reported columbic efficiencies of the order 73-90%.
The most successful previous type is the H2-02 fuel cell of the direct or indirect type. In the direct type, hydrogen and oxygen are used as such, the fuel being produced in independent installations. The indirect type employs a hydrogen-generating unit that can use as raw material a wide variety of fuel. The reaction taking place at the anode is as in Eq. (2), and at the cathode as in Eq. (3).2H2+4OH−→4H2O+4e−  (2)O2+2H2O+4e−→4OH−  (3)
Because of the low solubility of H2 and 02 in electrolytes, the reactions take place at the electrode/electrolyte interface, requiring a large area of contact for a large electron flow. This is obtained with porous materials called upon to fulfill the following main duties: the materials must provide contact between electrolyte and gas over a large area, catalyze the reaction, maintain the electrolyte in a very thin layer on the surface of the electrode, and act as leads for the transmission of electrons.
One unmet challenge has been to produce hydrogen and oxygen from photosynthetically generated biomass, without harsh chemical alteration, genetic modification, or combined approaches, such as prokaryote and eukaryote using the power of sunlight as the preferred embodiment.
Another challenge has been the creation of a method of generating current to power the system when there is low sunlight or in the nocturnal cycle.
Present systems fail to provide scalability and low cost and cannot be incorporated into a system that continuously produces these valuable gaseous byproducts as part of a grow system where other valuable products are generated such as food and fuels.
Furthermore, the use of photosynthetic material to generate the constituent gases of fuel cells is of interest, as this type of energy (provided it was generated from photonic activity) would be a panacea for low-cost renewable energy production.